Thesis on Circular Jacquard knitting machine

Abstract Knitting is a process of fabric manufacturing from a strand of yarn. In this process two types of machines are used circular knitting machine & flat bed knitting machine. A knitting machine is thus an apparatus for applying mechanical movement, either hand or power derived, to primary knitting elements, in order to convert yarn into knitted loop structures. First hand operated Circular knitting machine was produced in 1860. In the year 1870 first mechanical circular knitting machine was produced. Machines may range from high-production, limited-capability models to versatile, multi-purpose models having extensive patterning capabilities. The more complex the structure being knitted, the lower the knitting speed and efficiency. The simplest of the knitting machines would be hand-powered and manipulated whereas power driven machines may be fully automatically-programmed and controlled from a computer system. Electronic jacquard circular knitting machine is one of the powers driven fully automatic computerized machines. This invention has opened up a vast area for knitting. Proper use of this invention may lead to a knitted fabric of better physical properties & serviceability. This proposed thesis will give a better idea to minimize the cost a knit fabric while increasing the properties, serviceability, appearance etc. Also attempts to maximize the profit range with minimum investment. Introduction During the 20s of the 20th century knitted upper garments for the first time entered the fashion. Whenever knitwear entered the fashion, fashion was through its demand encouraged further development of some kind of knitting machines. Consequently, the circular knitting machines with latch needles developed the increasing possibilities of patterning. In Chemnitz, in 1921, jacquard circular machine was constructed, which allows creation of different patterns in color, and in 1927 steel tape for patterning was introduced [1]. Knitting technology continues to expand the capabilities for conversion of fiber and yarns into knitted products. Obviously, there are developments that have improved capabilities such as production speed and production efficiency, patterning limitations etc. The present thesis relates to a jacquard circular knitting machine, more especially to a jacquard circular knitting machine provided with a needle cylinder driving mechanism capable of optionally and readily changing the rotary motion of the needle cylinder of the circular knitting machine according to the pattern to be produced on the fabric [5]. A jacquard circular knitting machine includes a cylindrical needle cylinder provided with a plurality of knitting needles, a patterning mechanism for controlling the vertical sliding motion of the knitting needles on the knitting cylinder to knit a jacquard knitted fabric, and a driving mechanism for driving the needle cylinder. Usually, the patterning mechanism employs a pin drum or pin drums for controlling the knitting needles [2]. In recent years, however, computers have been employed in the patterning mechanism. A patterning mechanism employing a computer, namely, a computerized patterning mechanism, has an infinite patterning capacity [3]. That is, by controlling all the individual knitting needles, the computerized patterning mechanism is capable of changing stitches along the wale direction and is capable of producing diversified patterns in the course direction, as compared with the pin drum type patterning mechanism. Furthermore, the computerized patterning mechanism has the advantage that it enables quick and very easy pattern changes without requiring a skilled worker [2]. Mechanical & electronic circular jacquard machines are very much useful & versatile in nature but to do maximum use of these machines it is important to have proper knowledge about their driving & patterning mechanism. The changed property of the fabrics produced from circular jacquard knitting machines from conventional circular knitting machines is also a purpose of the study. To change the demand of the world knit industry the versatile use of this jacquard knit machines are very important. In Bangladesh the use of these latest machines are not quite up to the mark just because of lack of knowledge about these machines. The main purpose of the study is to make the circular knit jacquard machines mechanism more familiar with knit industries & find out its versatility. Objective In this study the main objective is to understand the mechanism of the circular jacquard machine. Patterning system to produce a design knit fabrics. Also try to find out the difference in mechanism between mechanical jacquard & electrical jacquard machines. Another object is to find out the difference in properties among the fabrics produced by conventional knitting machine & jacquard knitting machine with different type of yarn used. Methodology 1. At first types of jacquard circular knitting machines were determined. 2. Detailed information about different parts of the machines one by one from the machine with their mechanism of work. 3. Then comparative study about patterning various designs was done. 4. Different patterned fabrics were tested to compare with knit fabrics produced from circular knitting machines. Development of Circular Knitting Machine [4] 16th century 17th & 18th Century 19th century 20th century In 1589, William Lee, a clergyman, invented the first knitting machine, which knit 8 loops to 1 inch of width. This was during the reign of Queen Elizabeth I. He worked nine more years to develop a machine that could knit 20 loops per inch for silk stockings. Thus, during this era, the manufacture of stockings became very important to many British and these were sent to the Netherlands, Spain and Germany. It was also considered fashionable for the men of those times to wear fitted stockings under short trunks. Queen Elizabeth I herself wore silk stockings which were finer, softer and much more expensive. After the invention of the first knitting machine, the art of knitting was gradually taken over by guild-organized cottage industries in the 17th and 18th centuries The Industrial Revolution, which started in the late 18th century in Britain and spread throughout the world, played a key role in spreading wool spinning and cloth manufacture to factories. The full-fashioned knitting machine was invented in 1864 by William Cotton of Leicestershire, England. This machine was a part of the original model by Lee. Also known as the lace market, the city of Nottingham dominated the production of machineknitted lace during the Industrial Revolution and the following decades. In the 19th century, power was applied to the knitting machines and subsequently, circular-knitting machines appeared on the scene. Seamless stockings were knitted on circular machines. England became famous for its stockings. In fact, the word hosiery is derived from the old English word "hose" which means a covering for the leg. Initially cotton, wool, silk and later rayon yarns were used for making hosiery. Then came 21st century nylon in the 1940s when women preferred nylon hose. The use of nylon improved the fit of hosiery due to its stretchable properties. Subsequently, in Great Britain, hosiery came to be associated with all types of machine-knit garments which is also known as knitwear. In the United States, hosiery products are still known as stockings, socks, panty hose, and tights. Knitwear was mainly associated with women's fashion, but later on, knitted pullovers, cardigans, shirts, men's underwear, sportswear, and swimwear also became popular. Developments in the 20th century led to an increase in the production speeds of knitting machines and offered a wider choice to pattern the knitted fabrics. Now, computer controlled knitting machines have entered the scene, and these are highly versatile. Today, knitted garments have evolved as fashionable and functional wear for men, women and kids. Circular jacquard knitting machine Can be classified in two types [16]: 1. Mechanical jacquard. 2. Electrical jacquard. Mechanical jacquard: Generally the Jacquard machines were mechanically processed. The patterns which required are mechanically introduced in the machine [6].  Circular mechanical jacquard machine knitting elements: Peg Box Peg Selector Cam Box Jack Cam, Needle Cam, Pin Cam, Sinker Cam Jack Needle Pin Sinker  Circular Mechanical Jacquard Selection System [9]: In the past, a variety of mechanical Jacquard selection systems were available on the market, but today manufacturers privilege only two types of mechanical Jacquard systems, equipped respectively with - Needle sliders or - Pattern wheels The slider selection system is the most commonly used system. Under each needle there is a slider with 3 butts: a lower butt for needle raising, an upper butt for loop knocking-over and an intermediate selection butt that can be positioned at different levels. A selection lever acts on the intermediate selection butt. When the lever is idle (i.e. in external position) the slider maintains a vertical position and is pushed upward by the raising cams so that the corresponding needle can assume a working position. When the selection lever is active (i.e. in internal position) the slider is pushed into the guide groove and the corresponding needle assumes a non-knitting position. The selection lever is controlled externally and each manufacturer has developed its own solution to control the selection lever (e.g. fixed turrets with plug-in cartridges for pattern selection, punched cards system, reeds etc.) Fig: Mechanical slider selector The most recent models of circular knitting machines incorporate 37 selection levels (mini-jack machines). On double-bed machines, the selection levels are limited to the cylinder. In addition to the pattern selection levels, these machines also feature two extra levels to facilitate the selection change-over procedures The selection butts of sliders are usually arranged as follows: - Diagonally - Symmetrically Fig: Butt position With the slider butts arranged diagonally, the pattern design includes in its width a number of wales equal to the number of selectors. In symmetrical arrangement, the width of the pattern design is twice the number of selection levels. The sliders arrangement can remain unchanged for each machine revolution (fixed arrangement), and in this case the height of the design pattern is given by the number of feed systems of the machine divided by the number of pattern colors. If the operator wishes to modify the height of the pattern, the arrangement of the sliders must be changed after every machine revolution. This operation can be carried out by applying different methods, i.e.: - Using small cylinders provided with as many holes as the number of selectors; each hole can have a peg to exclude the corresponding selector. These small cylinders can be rotated after each machine revolution to modify the slider selection on a specific feed system. - Using selection turrets that can be reset and provided with a new selection scheme for each machine revolution.  Circular mechanical jacquard machine knitting mechanism: 1. There are 39 pegs in a peg box. Top 3 are fixed or common butts. Rest 36 for design (means in a repeat of a course there may be 36 Wales maximum). Peg box: inside view outside view 2. Each peg controls a single needle. 3. Each peg box makes a single course like a feeder and can produce 36 wales in a repeat of a course. 4. As cylinder moves anti clockwise, needles get peg of a peg box at the left side first. If no peg is pressed all needles are active and can produce all knit loops. 5. If left (peg) is pressed, it press selector and disconnect corresponding needle and forms miss loop. 6. If only right (peg) is pressed, it press selector and disconnect corresponding needle after forming a half loop and it forms tuck loop. Electrical jacquard: A jacquard circular knitting machine is disclosed provided with a needle cylinder driving mechanism capable of optionally and readily controlling the rotary motion of the needle cylinder according to the pattern to be knitted [7]. A motor interlocked through gears or the like with the needle cylinder rotates according to a needle cylinder rotating procedure stored previously in a magnetic memory medium [3]. Needle actuators operate according to a pattern forming procedure stored in another magnetic memory medium as a signal is provided by a sensor for sensor for detecting the rotary motion of the needle cylinder [8]. Thus a jacquard circular-knitted fabric having predetermined patterns can be knitted efficiently.  Electrical circular jacquard knitting machine knitting elements:       Electromagnetic needle selector. Spring Jack. Jack Cam Box and Jack cam. Needle Sinker Special cam box for electrical circular jacquard. Electromagnetic needle selector Spring Jack Jack Cam Box and Jack cam Needle Sinker ENS (electromagnetic needle selectors) Special cam box for electrical circular jacquard  Electrical Jacquard Selection System [9]: The precise definition of this needle selection system for circular knitting machines is “electromechanical selection with electronic control”, based on the use of piezoelectric actuators. That act on the selectors or of a magnet which commands a striker placed under the needle. Fig: A 16 (8+8) level piezoelectric actuator If the selection is carried out with a single magnet, when the magnet is excited, the striker assumes a vertical position thanks to the action of a control spring then reaches the rising cam and forces the needle in the working position. When the magnet is not excited, the spring withdraws the striker into the groove in the non-knitting position together with the corresponding needle. Fig: Electromechanical selection with single magnet The “needle-by-needle” selection allows the knitting of design patterns of almost unlimited Size since each needle can be independently set in the knit, tuck or miss position. The electronic Selection is now widely used for the needles of the cylinder, while on several double-bed knitting Machines, the selection of dial needles is still Carried out mechanically with cams and tracks. However, many machine manufacturers also offer Electronic dial and cylinder needle selection systems.  Circular electrical jacquard machine knitting mechanism [10]:  Formation of knit loop: For every knitting heads the needles stands on the head of the jack and the needle has no raising cam. So when the jack pushes the needle upwards only then the needle forms a knit loop. Every jack cam box contains two raising cam side by side. The left raising cam leads a needle to the clearing position with help of the needle cam because both raising jack cam are came height of the yarn taking height. For the both raising cam there are two ENS one for each. The spring jack constructed in the way that there is no interruption its butt always follows the raising cam. So when the magnet remains neutral the raising cam push the jack and jack push the needle so form the knit loop. Fig: Needle action for knit loop  Formation of tuck loop: When we need to form a tuck loop no electricity passes through the first ENS so it remains magnet and attract the jack and jack become detached from the raising cam and the needle keeps it position in the down. So no clearing action is happened. But electricity passes through the second ENS which makes the second ENS neutral and jack moves upward following the raising needle and so needle. In here needles raises only to the yarn taking height not in the clearing position so the old loop tucked in the latch and take the new yarn. Following the next knit loop a tuck loop is formed. Fig: Action of magnet & Jack  Formation of miss loop: When miss loop is required no electricity passes through neither ENS nor the ENS keeps the jack detached from the raising cam whole the time. So needle remains in the bottom most position. So neither clearing nor the yarn taking takes place. In this way miss loop is happened. Fig: Needle butt set out in multiple cam tracks Formation of special knit design [3] Two or more colored yarns may be used during knitting for value addition i.e., aesthetic value in one hand and better marketability on the other. Addition of more than one colors results horizontal stripe, vertical stripe, check or some special effect depending upon the combination of colored yarns and the order of selection of needles making the loops using different colors. Production of stripe in width direction (course wise) is very simple. It does not require any specific order of needle selection but arrangement of colored yarns in regular order (interval) during feeding will produce the desired effect. However to produce special effect or motif, selection of needle is essential along with feeding two or more colored yarns. Generally two or more colors are used in the same course (resultant) to produce the desired effect and accordingly two or more neighboring feeders make one complete course with proper needle selection. A few multi-colored weft knitted structures are shown here. Fig: Effect of colored yarns on knitted structures However, in order to make black and white representation of the colored effect the presence of different colors on the surface of the knitted structures have been shown by the characters R, G, B etc. where R, G, B etc. stands for different colors. Two more simple motifs produced on two colors – black and white – are shown. The first one (a) repeats on 24 × 24 courses and wales whereas the second one (b) repeats on 20 × 28 courses and wales. Fig: Motifs in black & white Experiment of Physical Properties Materials & Methods  Materials:  Yarn selection: As the experiment has done only for identifying the changes between the fabrics of circular knitting machine & circular jacquard knitting machine so all the yarns used were same for both the machines. Only change was in their design.  Knitting machine: Knitting Machines (Mayer & Cie, Germany) with same diameter of cylinder but difference was one was single jersey circular knitting machine & another was single jersey circular electric jacquard machine.  Methods:  Dyeing: All the yarns were dyed with same average color in a same machine at the same time. Dyeing process was carried out at 60°C on PH 9-1.2 with M: L Ratio 1:10 for 60 minutes.  Finishing: Finishing has a strong impact on fabric properties. The finishing operation had done in several steps. Firstly Slitting had done immediately after the dyeing to make the tube fabric open by cutting the fabric through a preset needle line. Secondly Drying was carried out by monforts dryer which had been used to dry the wet fabric for the further smooth operation. Silicone softener (60g/l) was used at 30% overfeed at 130°C. At last stentering and compacting operation had done.  Relaxation: Knitted fabrics are very much prone to extend and shrink. So proper relaxation before any kind of test is very much essential, especially for dimensional properties. The fabrics had been kept at standard atmosphere of 27°C and 65% Relative Humidity for 24 hours at Physical Lab.  Determination of fabric weight (GSM): After relaxation & conditioning of knit fabric samples, GSM of samples were tested by taking test samples with the help of GSM cutter & weighting balance (electronic) [11].  Determination of spirality: First cut a sample of (50cm×50cm) with the scissors. Then by the over lock sewing m/c the 4 ends of the cut fabric were sewn. After sewing, again by a scale mark (35cm×35cm) on the fabric & then sample washed with a standard soap solution (1g/l). After washing the sample was tumble dried at 65°C± 15°C for 60 minutes. Then after cooling the sample tested with the shrinkage tester scale also the spirality was tested. Shrinkage was tested length wise & width wise along the mark of (35cm×35cm). And spirality was tested along sewing line alignment. (Distortion of the formation of loops) [12].  Determination of bursting strength: Bursting strength of samples was measured by an automatic bursting strength tester. Samples are gradually set on the diagram, the automatic bursting strength tester, measures time, distortion, pressure & the flow rate to burst the fabric. For different samples we recovered there parameters. [13]  Determination of fabric shrinkage: Shrinkage is an inherent property of knit fabrics which can’t be prohibited, but for better quality, it must be controlled in a systematic way. After tumble drying & cooling of the fabric, shrinkage of this samples are in widthwise. It was calculated from the difference in fabric length before and after washed garment according to AATCC test methods 135 and 150 [14]. Result & discussion:  Effect on fabric weight (GSM): From the following figure, it is seen that the greater the compactness of the fabric, the greater the GSM of the fabric is found. As in the higher compactness of the fabric of jacquard knitting machine due to patterning, is greater so the GSM rises from circular knitting machine to circular jacquard knitting machine according to compactness. Fabric GSM 250 200 GSM 150 100 Series 1 50 0 Plain Knit Fabric jacquard knit (design) jacquard knit (Compact) Fabric Type  Effect on fabric shrinkage: From the experiment it is seen that the shrinkage of fabrics made from jacquard knit machine is variable according the design. Whereas there is no such differences in the fabrics of circular knit machine. Fabric Shrinkage 9 8 Shrinkage % 7 6 5 4 Length wise 3 Width wise 2 1 0 Plain Knit Jacquard Knit (Design) Jacquard Knit (Compact) Fabric Type Effect on fabric bursting strength: From the experiment it is seen that the normal knit fabric show comparatively low bursting strength than jacquard knit fabric. The reason behind that is jacquard fabric has more floated yarn in a square meter than a normal knit fabric. Bursting Strength 350 300 250 KPa  200 150 Bursting Strength 100 50 0 Plain Knit Jacquard Knit (Design) Fabric Type Jacquard Knit (Compact)  Effect of fabric spirality: Though no of feeder plays an important role with spirality but it is seen from the experiment that jacquard knit fabric shows less spirality than knit fabric with same no of feeder. Spirality 2.5 Percentage (%) 2 1.5 Spirality 1 0.5 0 Plain Knit Jacquard Knit (Design) Jacquard Knit (Compact) Fabric Type Special Properties of Jacquard Knit Machine 1. Pattern change: Fast pattern change helps reduce downtimes and improves the efficiency of the machine. Pattern change can be carried out quickly and easily with all types in the electronic ranges [2]. All necessary pattern data are transferred onto a floppy disk, which can be created quickly and easily using the pattern preparation system. The floppy disk becomes the master and is read into the machine controller. This converts the pattern information into knitting information and passes it on to the PIEZO selection unit. But new pattern ideas can also be implemented quickly and easily on the Jacquard machines by direct means and, if necessary, via the Internet [3]. Patterns that have once been read in can be modified retrospectively using easily understood functions. All pattern data remain stored in the event of a supply failure or when the machine is switched off. This means no loss of quality in the knit due to pattern offset when restarting. 2. Repeat of design: In jacquard circular knitting machine each and every needles can be controlled using peg or jack. It is very easy to produce a design of very long repeat [8]. Whereas auto stripping machine has only 100 course for repeat & normal knit machines has its limitations according to the number of feeder. Some examples of circular jacquard knitted fabric with long repeat are given below: Fig: Fabric with long repeat 3. Replace printing: Computerized patterning system allows producing fabric like printing using dyed yarn [15]. Setting up a printing plant is comparatively costly than a circular electric jacquard machine. The step of printing can be removed using knitting jacquard machine. Some examples of circular jacquard knitted fabric with printing like pattern are given below: Fig: Fabric with print design 4. Multiple yarns in one repeat: Any number of yarns of different colors or different count or different specifications can be used for one repeat which gives the fabric versatile design. Fig: Multiple yarns in one repeat 5. Design like woven fabric: Some stripes or designs which were only possible in woven fabric can now very easily developed in knit fabric using electrical jacquard circular knitting machine. Fig: Knit Fabric of woven design 6. Fabric with picture pattern: Introduction of CAD system in jacquard machine [8] allows vast space for design single jersey knit fabric. Picture of any people or any scenario or any logo can be developed in the fabric without any problem. Fig: Needle action in Jacquard fabric Fig: Logo of SFL in Jacquard fabric Conclusion This study has reveled full mechanism of circular jacquard knitting machine with the properties of fabric that differs from circular knitting machine. If jacquard machine is used according to its merit, than it can be a great profit for the world growing knitting industry. Only drawback of jacquard machine is its RPM. Jacquard machine gives only 20-30 kg design fabric per 8 hour shift whereas circular knitting machine gives 300 kg plain fabric per 8 hour shift. This problem is increasing the cost of the jacquard fabric production. To produce a single jersey knit fabric production cost is approximately 7-10 tk/kg but for single jersey jacquard fabric the cost is about 250-300 tk/kg. Further research is recommended to reduce the price of jacquard fabric production. If do so then a vast area will be open for knitting industry. Paper can be replaced with jacquard fabric. That will be better for the environment as fewer trees will be cut to prepare paper. References 1. International, T., & Journal, I. (2011). Technological reasons for entering knits in the fashion of the 20’s, 1(7), 16–22. 2. Jacquard circular knitting machine. (1985, July 3). Retrieved from https://www.google.com/patents/EP0147139A2?cl=en&dq=knitting&hl=en&sa=X&ved =0ahUKEwjP8Ijagc7JAhUIBY4KHYjqAdcQ6AEIRjAG 3. Ray, S. C. (2012). Fundamentals and Advances in Knitting Technology. Fundamentals and Advances in Knitting Technology. Woodhead Publishing Limited. Retrieved from http://www.sciencedirect.com/science/article/pii/B9780857091086500181 4. http://sewjazzy.angelfire.com/timeline.htm 5. Jacquard-Rundstrickmaschine. (1985, July 3). Retrieved from http://www.google.com/patents/EP0147139A2?cl=de 6. Mechanical jacquard of computerized glove knitting machine. (2006, October 25). Retrieved from https://www.google.com/patents/CN2830442Y?cl=en&dq=mechanical+jacquard&hl=en &sa=X&ved=0ahUKEwip_4fV7NHJAhUmeaYKHdmRB34Q6AEIIDAA 7. Knitting : Fundamentals, Machines, Structures and Developments, N.Anbumani 8. Beyn, E. J. (1976). United States Patent 1191. 9. http://docslide.us/documents/textile-reference-book-for-knitting.html 10. Banerjee, P. K. (2014). Principles of Fabric Formation. CRC Press. Retrieved from https://books.google.com/books?id=ymVYBQAAQBAJ&pgis=1 11. ASTM D3776 / (2013), Standard Test Methods for Mass per Unit Area (Weight) of Fabric, American Society for Testing and Materials, West Conshohocken, PA, USA. 12. AATCC Test Method 187-2013, Dimensional Changes of Fabrics: Accelerated, 13. 14. American Association of Textile Chemists and Colorists, Research Triangle Park, N.C., USA, Developed in 2000. ASTM D3786 / 2013, Standard Test Method for Bursting Strength of Textile Fabrics, Diaphragm Bursting Strength Tester Method. American Society for Testing and Materials, West Conshohocken, PA, USA. AATCC Test Method 135-2012, Dimensional Changes of Fabrics after Home Laundering, American Association of Textile Chemists and Colorists, Research Triangle Park, N.C., USA, Developed in 2000. 15. George, M., & Ferrin, W. (1984). United States Patent [4841748]. 16. Spencer, D. (1996). Knitting technology. Knitting International. http://doi.org/10.1533/9781855737556